Abstract

                                Combinations of organic sources of nitrogen have exerted variable influence on growth and yield of rice. Study on relative efficacy of organic sources of nitrogen in low land rice revealed that combination of 50% N through fertilizer and 50% N through different organic sources (Glyricidia leaf (GL), Poultry manure (PM), Farm yard manure (FYM) and Neem cake (NC) produced significantly higher growth and yield parameters than other combination treatments. The growth and yield parametrs were at the lowest with 100% N through organic sources (FYM N,, +GL N,,) alone. Combinations of 50% N each through fertilizers and different organic sources (GL, PL, FYM and NC) recorded higher N uptake compared to the rest of the treatments..." Nitrogen supplied entirely through fertilizer registered the lowest soil fertility status. Maximum gross and net returns as well as high benefit cost ratio was obtained with 50 per cent substitution of inorganic nitrogen source with glyricidia leaf manure.

Key words : Nitrogen, Organic and Inorganic sources, Rice.